Water pipe boiler

ABSTRACT

A water pipe boiler having a circular or polygonal contour, which includes at least two heating surface cage bodies each comprising vertical pipes and upper and lower annular or polygonal headers or bends arranged coaxially one within the other in radially spaced relationship, while any of the individual cage bodies may be designed as evaporator, superheater, feed-water preheater or hot water generator.

United States Patent lnventor Willibald Kraus Grebenstein, Germany Appl.No. 11,438 Filed Feb. 16, 1970 Patented Jan. 11, 1972 AssigneeRheinstahl Henschel Aktiengesellschaft Kassel, Germany Priority Feb. 15,1969 Germany P 19 07 758.8

WATER PIPE BOILER 9 Claims, 3 Drawing Figs. U.S. Cl 122/235 R, 122/356Int. Cl F22b 21/00 Field of Search 122/235 P, 323, 356

[56] References Cited UNITED STATES PATENTS 2,630,104 3/1953 Harvey122/323 3,118,431 1/1964 Banker etaL. 122/323 2,271,880 2/1942 Wood122/235 X 2,898,892 8/1959 Campbell et al 122/356 PrimaryExaminer-Kenneth W. Sprague Attorney-Walter Becker ABSTRACT: A waterpipe boiler having a circular or polygonal contour, which includes atleast two heating surface cage bodies each comprising vertical pipes andupper and lower annular or polygonal headers or bends arranged coaxiallyone within the other in radially spaced relationship, while any of theindividual cage bodies may be designed as evaporator, superheater,feed-water preheater or hot water generator.

WATER PIPE BOILER The present invention relates to a water pipe boilerwith a circular or polygonal design and with boiler pipes arrangedvertically along the circumference of circular spiral or polygonal crosssections and forming draft guiding walls and with a horizontal flue gasflow through the high rectangular cross sections formed by the draftguiding walls.

Water pipe boilers are known in which between annular chambers there arevertical boiler pipes welded in, in such a manner, that they formgastight draft guiding walls. Between these walls, the flue gas flowshorizontally along circular paths or along the circumferential line ofthe polygonal draft guiding walls through the free, relatively verynarrow but high rectangular cross sections from the inside toward theoutside. The flow cross sections along the flue gas path may beconstant, or may be variable sectionwise, or in a continuous mannerwhile the cross sections likewise decrease with decreasing flue gastemperature. With boilers of this type, it is disadvantageous that inview of the geometry of the annular chambers, they are suitable for onlyrelatively small outputs and relatively low pressures.

It is, therefore, an object of the present invention to provide a waterpipe boiler which has the advantages of the abovementioned flue gasguiding system, but which is adapted to realize higher and maximum unitoutputs and also high pressures, also with superheaters and also withfeed-water preheaters.

These objects and other objects and advantages of the invention willappear more clearly from the following specification, in connection withthe accompanying drawing, in which:

FIG. 1 represents a diagrammatic cross section through a water pipeboiler according to the invention with four cage heating surfaces.

FIG. 2 illustrates on a larger scale than FIG. 1 a cutout of adevelopment of the cage heating surface of FIG. 1 with upper and lowerannular headers.

FIG. 3 is a diagrammatic cutout of the cage heating surface with bendsand finned pipes.

The above-outlined objects have been realized by the fact that two ormore cage heating surfaces are provided, each of which consists ofvertical pipes and upper and lower annular or polygonal headers or/andreversing bends, said cage heating surfaces being arranged substantiallycoaxially in radially spaced relationship to each other while theindividual cage heating surfaces are differently designed so as torepresent at least one evaporator, superheater, and/or feed-waterpreheater or hot-water generator.

According to the present invention, it is provided that one and the samecage has different heating surfaces, for instance, in the form of anevaporator and a superheater.

With regard to the flow through the cage heating surfaces, it isprovided that the individual cage heating surfaces are passed through bya medium only in upward direction or only in downward direction orupwardly and downwardly while the number of the upwardly and downwardlypassed through pipes equal each other or are different from each other.The number of the parallelly passed through pipes along thecircumference of the cage heating surfaces varies. Moreover, it isprovided that between two cages designed as draft guiding walls thereare provided one or more cages preferably as superheaters. Thesesuperheaters are at both sides in contact with evenly tempered fluegases passing therealong while the vertical pipes in the direction ofthe flow of the flue gas are spaced from each other by a distance whichequals or exceeds the diameter of the pipes.

With regard to the arrangement of the feed-water preheater, it isprovided that between the outermost cage forming a draft guiding wall onone hand, and the flue gas chamber mantle on the other hand, there areprovided one or more cages preferably in the form of feed-waterpreheaters which at both sides are passed around by evenly tempered fluegas and the pipes of which in the direction of flow of the flue gas arespaced from each other by a distance which equals or exceeds thediameter of the pipes. With the water pipe boiler according to theinvention, vertical pipes pertaining to the cages may be employed whichare equipped with fins, studs, or ribs.

Referring now to the drawing in detail, the cage heating surfaces l, 2,3 and 4 are coaxially arranged with regard to each other while the cageheating surfaces 1 and 2 serve as draft guiding walls with tangentpipes. The cage heating surface 1 forms an evaporator (the evaporatorpipes being marked by shading). All pipes of the cage heating surface 1are passed through by boiling water in upward direction and they are atthe upper and lower end welded into annular headers 7 (FIG. 2). Thewelded-in ends of the pipes are pulled in so as to assure a tangent pipearrangement.

The cage heating surface 3 has likewise been built up of tangent pipesas well as upper and lower headers similar to the showing in FIG. 2. Aportion of the cage heating surface 3 is formed by evaporator pipes(shaded), which are passed through in upward direction by boiling waterand in conformity with FIG. 2 consist of superheater pipes 6 which arepassed through by a medium in upward and downward direction. Directlyadjacent to the evaporator pipes are superheater pipes 6 passed throughby saturated steam. The annular headers are as to the medium separatedinto an evaporator part and a superheater part. Inasmuch as withincreasing superheating the volume flow increases likewise, whereas theflue gas temperature and thus the required pipe inner cooling decreases,it is advantageous to correspondingly increase the number of theparallelly passed through pipes along the circumference.

From the directional arrows indicated in FIG. 2 it will be seen thatfirst three pipes are passed through by the medium in downwarddirection, and finally, five pipes are passed through by the medium inupward direction. In the upper annular header 7 and the lower annularheader 8, axial flows occur so that the annular headers 8 simultaneouslyact as mixing chambers. In conformity with the symmetrically off-flowingflue gas as indicated by the arrow in F IG. 10, also the steam in thecage heating surface 3 flows symmetrically to both sides of the boilerpipe and from the latter to the flue gas exit slot 11 of the cageheating surface 3.

The cage heating surface 2, designed as superheater and provided withupper and lower reversing bends 13 is arranged between the cage heatingsurfaces 1 and 3 forming draft guiding walls. In conformity with thearrows 10 in FIG. I, the cage heating surface 2 is, on both sides,passed by, by evenly tempered flue gas. The vertical superheating pipesof the cage heating surface 2 have in the illustrated example in theflow direction of the flue gas, a distance from each other which exceedsthe pipe diameter.

In the illustrated example, between the outermost cage 3 forming a draftguiding wall, and the flue chamber mantle 12, there is provided the cage4. This cage 4, which is designed as feed-water preheater, is providedwith upper and lower bends 13 in conformity with FIG. 3 and also withfinned pipes 14. This cage 4 is, in conformity with the arrows l0,likewise passed around on both sides by evenly tempered flue gas.Outside the flue gas chamber mantle 12 there is located the insulation15. The combustion gases flow from the combustion chamber 16 inconformity with the arrows 10 through the slot 17 of cage 1, and throughthe slot 11 of cage 3 to the exit or discharge 18.

The advantages realized by the present invention consist primarily inthat the individual cage heating surfaces may be manufacturedindependently of each other. These individual cage heating surfaces areeasily subjected to a pressure test. Major repairs such as thereplacement of old pipes are greatly simplified, inasmuch as individualcages can easily be exchanged. The structure according to the inventionfurthermore permits a considerable reduction in the manufacturing time,and also permits a simple manufacture of cage heating surfaces to bekept in stock.

It is, of course, to be understood that the present invention is, by nomeans, limited to the particular showing in the drawing, but alsocomprises any modifications within the scope of the appended claims.

What I claim is:

l. A water pipe boiler of a closed contour design, especially of acircular and polygonal contour design, which includes at least twoclosed heating surface cage bodies substantially coaxial with regard toeach other and arranged open in radially spaced relationship to eachother, each of said closed heating surface cage bodies comprisingpredominantly upright straight pipes arranged in wall to wall contactwith each other and also comprising upper and lower connecting meansrespectively establishing flow connection between the upper ends andlower ends of said vertical pipes, said individual cage bodies beingadapted to be connected to different sources of media for respectivelyrunning said cage bodies selectively as different types of cage bodies.

2. A boiler according to claim 1, in which said upper and lowerconnecting means are formed by headers permitting independent cage bodyexpansion.

3. A water pipe boiler of a closed contour design, especially of acircular and polygonal contour design, which includes at least twoheating surface cage bodies substantially coaxial with regard to eachother and arranged in radially spaced relationship to each other each ofsaid heating surface cage bodies comprising upright pipes arranged inwall-to-wall contact with each other and also comprising upper and lowerconnecting means respectively establishing flow connection between theupper ends and lower ends of said vertical pipes, said individual cagebodies being adapted to be connected to different sources of media forrespectively running said cage bodies selectively as different types ofcage bodies, said upper and lower connecting means being formed bybends.

4. A boiler according to claim 3, in which at least one and the same ofsaid closed heating surface cage bodies comprises different grouped pipetypes of cage bodies.

5. A boiler according to claim 4, in which at least one and the same ofsaid closed heating surface cage bodies includes an evaporator heatingsurface and a superheater heating surface.

6. A water pipe boiler of a closed contour design, especially of acircular and polygonal contour design, which includes at least twoheating surface cage bodies substantially coaxial with regard to eachother and arranged in radially spaced relationship to each other, eachof said heating surface cage bodies comprising upright pipes arranged inwall-to-wall contact with each other and also comprising upper and lowerconnecting means respectively establishing flow connection between theupper ends and lower ends of said vertical pipes, said individual cagebodies being adapted to be connected to different sources of media forrespectively running said cage bodies selectively as different types ofcage bodies, at least one and the same of said heating surface cagebodies comprising different types of cage bodies, different verticalpipes of one and the same type of cage body respectively being passedthrough by the respective medium in opposite directions.

7. A boiler according to claim 6, which includes two closed cage bodiesforming draft guiding walls and also includes at least one superheatercage body interposed between said draft guiding walls in radially spacedrelationship thereto so as to permit evenly tempered flue gas to passopenly on both sides of said superheater cage body, the vertical pipesof said superheater cage body being spaced from each other by a distanceequaling at least the diameter of said last-mentioned vertical pipes.

8. A boiler according to claim 6, in which the outermost heating surfacecage body forms a draft guiding wall and is surrounded in radiallyspaced relationship by the outer wall of said boiler, and which includesat least closed one cage body forming a feed-water preheater and beingarranged in radially spaced relationship to and between said outermostcage body and said outer wall of said boiler to permit being passed byon both sides thereof by evenly tempered flue gas, the vertical pipes ofsaid feed-water preheater bein spaced from each ot er by a distanceequaling at least the iameter of said lastmentioned vertical pipes.

9. A boiler according to claim 6, in which said vertical pipes haveenlargements increasing pipes surfacing on the outside thereof.

1. A water pipe boiler of a closed contour design, especially of acircular and polygonal contour design, which includes at least twoclosed heating surface cage bodies substantially coaxial with regard toeach other and arranged open in radially spaced relationship to eachother, each of said closed heating surface cage bodies comprisingpredominantly upright straight pipes arranged in wall to wall contactwith each other and also comprising upper and lower connecting meansrespectively establishing flow connection between the upper ends andlower ends of said vertical pipes, said individual cage bodies beingadapted to be connected to different sources of media for respectivelyrunning said cage bodies selectively as different types of cage bodies.2. A boiler according to claim 1, in which said upper and lowerconnecting means are formed by headers permitting independent cage bodyexpansion.
 3. A water pipe boiler of a closed contour design, especiallyof a circular and polygonal contour design, which includes at least twoheating surface cage bodies substantially coaxial with regard to eachother and arranged in radially spaced relationship to each other each ofsaid heating surface cage bodies comprising upright pipes arranged inwall-to-wall contact with each other and also comprising upper and lowerconnecting means respectively establishing flow connection between theupper ends and lower ends of said vertical pipes, said individual cagebodies being adapted to be connected to different sources of media forrespectively running said cage bodies selectively as different types ofcage bodies, said upper and lower connecting means being formed bybends.
 4. A boiler according to claim 3, in which at least one and thesame of said closed heating surface cage bodies comprises differentgrouped pipe types of cage bodies.
 5. A boiler according to claim 4, inwhich at least one and the same of said closed heating surface cagebodies includes an evaporator heating surface and a superheater heatingsurface.
 6. A water pipe boiler of a closed contour design, especiallyof a circular and polygonal contour design, which includes at least twoheating surface cage bodies substantially coaxial with regard to eachother and arranged in radially spaced relationship to each other, eachof said heating surface cage bodies comprising upright pipes arranged inwall-to-wall contact with each other and also comprising upper and lowerconnecting means respectively establishing flow connection between theupper ends and lower ends of said vertical pipes, said individual cagebodies being adapted to be connected to different souRces of media forrespectively running said cage bodies selectively as different types ofcage bodies, at least one and the same of said heating surface cagebodies comprising different types of cage bodies, different verticalpipes of one and the same type of cage body respectively being passedthrough by the respective medium in opposite directions.
 7. A boileraccording to claim 6, which includes two closed cage bodies formingdraft guiding walls and also includes at least one superheater cage bodyinterposed between said draft guiding walls in radially spacedrelationship thereto so as to permit evenly tempered flue gas to passopenly on both sides of said superheater cage body, the vertical pipesof said superheater cage body being spaced from each other by a distanceequaling at least the diameter of said last-mentioned vertical pipes. 8.A boiler according to claim 6, in which the outermost heating surfacecage body forms a draft guiding wall and is surrounded in radiallyspaced relationship by the outer wall of said boiler, and which includesat least closed one cage body forming a feed-water preheater and beingarranged in radially spaced relationship to and between said outermostcage body and said outer wall of said boiler to permit being passed byon both sides thereof by evenly tempered flue gas, the vertical pipes ofsaid feed-water preheater being spaced from each other by a distanceequaling at least the diameter of said last-mentioned vertical pipes. 9.A boiler according to claim 6, in which said vertical pipes haveenlargements increasing pipes surfacing on the outside thereof.